Johan Cruyff wants you to read this. So do Oliver Kahn, Martin O’Neill and Luis Figo. They are just some of the luminaries who have expressed their support for a campaign to raise funds to build a memorial to Patrick O’Connell. You know, the former Ireland and Manchester United captain who saved Barcelona from extinction, guided Real Betis to their only La Liga title and died destitute in London, where he lies in an unmarked grave.

O’Connell grew up in Dublin and played junior football before gaining his first professional contract with Belfast Celtic in 1909. As a commanding central defender he impressed sufficiently to be purchased by Sheffield Wednesday (along with the left-back Peter Warren, the pair costing a combined fee of £50) but his career did not take off and, after three seasons in which he failed to get a regular game, he moved to Hull City.

He played more consistently there but it was his performances for a not-yet independent Ireland that really attracted the attention of bigger clubs, especially when they won the British Home Championship outright for the first time in 1914. Ireland beat Wales 2-1 in Wrexham and then gained their first away victory over England – a 3-0 trouncing at Ayresome Park – before claiming the title with a 1-1 home draw with Scotland, a match in which O’Connell excelled despite a broken arm. And not just any old broken arm, but one of his own. A month later Manchester United paid £1,000 to buy O’Connell from Hull. Three months later the first world war broke out.

It was not expected to last very long. Blundering into murderous conflict was one thing but there seemed no need to do anything so rash as to cancel the football season. As the carnage dragged on and sucked in more and more people, the prospects of the football season continuing uninterrupted grew dimmer. That was the context for the most controversial Liverpool-Manchester United match of all time.

On 2 April 1915 Liverpool, comfortably mid-table, hosted United with the visitors needing a win to escape relegation. George Anderson scored twice to give United victory and condemn Chelsea (with Tottenham Hotspur) to the drop instead but there was something whiffy about the game: from early on in the match spectators vented their contempt for the seemingly contrived proceedings, jeering misplaced passes and the apparent lack of application. After the game bookmakers reported an unusually large amount of money had been placed on United winning 2-0 at 7-1.

The Football Association opened an investigation to establish whether the result had been “squared” by the players. It later ruled that three United players and four from Liverpool had conspired to fix the result, with Jackie Sheldon, a former United player who had moved to Liverpool, identified as the ringleader. Others had been approached to take part but refused, notably Liverpool’s captain Fred Pagnam, who gave evidence against his team-mates during the investigation, and United’s goalscorer, Anderson. United’s star player, Billy Meredith, said that he felt something fishy was afoot when his team-mates seemed unusually reluctant to pass to him.

When banning the seven players for life, the football authorities showed little sympathy for the belief that the reason the players had arranged the scam was they were eager to ensure some earnings before the war caused the suspension of the league and the loss of their livelihoods. O’Connell was not one of the players found guilty but the role of United’s captain in the day’s events seemed curious. When United were awarded a penalty with the score at 1-0, O’Connell, not known for his prowess from the spot, demanded to take it. He booted it so far wide it looked like a deliberate miss and it was several minutes before play resumed, the referee feeling the need to consult with other officials, perhaps to see if he should order a re-take or even abandon what was turning into a farcical contest.

Some suggested the penalty was proof that O’Connell was not involved in the plot: after all, if he was, why would he squander the chance to make it 2-0? Others suggested he missed both to get himself off the hook and because he knew another goal was due anyway. “I don’t whether he was involved,” says the player’s grandson, Mike O’Connell. “But he would have had it in him, he would have enjoyed the intrigue, and I am certain that he was a marked man after that.”

The Football League was suspended after that, just as the players had feared (when the league resumed in 1919 the top-flight was expanded from 20 to 22 teams and Chelsea, following lobbying on their behalf by Liverpool, were allowed to stay up – but, infamously, Spurs were not; Arsenal, who had finished fifth in the second tier in 1915, were promoted instead). O’Connell spent the war working in a munitions factory in London, where he lived with his brother, Larry, an interesting character in his own right, being, in the words of Mike O’Connell, “a superb part-time opera singer, a fanatical Catholic and a fanatical womaniser” as well as a civil servant who successfully sued the British government for discriminating against him for being Irish.

Unable to find a club in England to take him on after the war, Patrick played a season with Dumbarton in Scotland before ending his playing days in the north-eastern league with Ashington, whom he then took over as manager. Then he disappeared. Or rather, he walked out on his wife and their four children. The only clue they had to his whereabouts over the following years were envelopes from Santander containing Spanish currency.

Yes, O’Connell was in Spain, where to this day he is remembered much better than he is in Britain or Ireland. In 1922 O’Connell replaced the Englishman Fred Pentland as manager of Racing Santander, whom he guided to five regional titles before they were nominated as one of the founders of the Spanish league in 1928. There followed a two-year stint at Real Oviedo before he was appointed manager of Real Betis Balompié, a second division team formed by workers alienated by the snootiness of the city’s top club, Sevilla. “He changed everything at the club,” says Julio Jiménez Heras, Real Betis’ public relations officer and an enthusiastic supporter of the campaign to build a memorial to O’Connell in Ireland.

“His professionalism was amazing, his fitness and tactical ideas ahead of his time. Plus he was really warm and charismatic, his players loved him. The people loved him too as he became a well-known and respected character around the city. I think he found a second home here. He used to say that he loved Sevilla because the people here live life like it is their last day on Earth.”

Under “Don Patricio”, as he was affectionately known, Betis were promoted from the second division in 1932 and three years later they stood on the brink of an unprecedented and highly improbable achievement: they went into the last match of the season one point ahead of Real Madrid at the top of the table. “This was extraordinary because Betis had no top players and could never pay big fees but he created great organisation and wonderful team spirit,” says Jiménez Heras. Betis’ triumph in the 1934-35 season was based on an almost impregnable defence, as they conceded almost half the number of goals as anyone else in the league. As it happened, Betis’ last match of the season was at O’Connell’s old club, Santander.

The night before the game Don Patricio dropped in to renew acquaintances with his former charges. One story that has since emerged is O’Connell asked the players to take it easy the next day but the Santander players responded they could not because their chairman, José María de Cossio, was pro-Real Madrid and had offered them a large bonus to beat Betis. However, no evidence of such an exchange has been produced. As it happened, Betis ran out 5-0 winners, their most emphatic away victory of the campaign.

O’Connell did not just meet success and acclaim in Betis, he also met another wife, who, improbably, was also Irish, also named Ellen and looked very similar to the woman back in England to whom he was still married. While the coincidence was quirky, the bigamy was an open secret in Sevilla, though was not mentioned so much during the couple’s holidays in Ireland.

Patrick O’Connell, centre, arrived at Barcelona in the 1934-35 season after taking Betis to first place in the League Championship the previous term. Photograph: FCB

O’Connell’s extraordinary success at Betis attracted the interest of Barcelona. The Irishman moved to the Catalan capital as Spain was edging closer to civil war, thus positioning himself firmly on the wrong side of Franco. With the political and economic situation worsening, Barcelona were struggling to stay afloat. They asked some of their foreign players, including the Uruguayan forward Enrique Fernández and Hungary’s Elemer Berkessy, not to return from holidays home. O’Connell was asked to stay and he agreed.

The situation deteriorated as full-scale war erupted in July 1936. The league was suspended but Barcelona played on in a regional division, consolidating its symbolic power in their resistance to the central regime. In August 1936, the man who had appointed O’Connell, the Barcelona president and prominent Catalan activist, Josep Sunyol, was arrested by pro-Franco forces and killed. O’Connell was on holiday in Ireland and club officials sent him a message explaining they would understand if he did not return. He returned.

As the fighting intensified and the turmoil and tension engulfed Barcelona, the club lurched to the brink of bankruptcy. A lifeline came in 1937 when a Catalan businessman who had emigrated to Mexico, Manuel Mas Soriano, asked the club to tour his new home country, where the socialist government was hostile to Franco.

O’Connell rounded up his players and staff and sailed to Mexico, where they played six matches before carrying on to New York for four more exhibition games. The tour cost the team most of their players, as only four travelled with O’Connell back to Barcelona, the rest either seeking asylum in Mexico or jumping out in France on the way back. But the money made from the expedition saved Barcelona from going under. O’Connell went back home to Ireland shortly afterwards but he had ensured Barcelona’s future and his own enduring memory.

O’Connell did return to Spain during the second world war but without the success of before. He even briefly took charge of Sevilla, though that did not diminish his place in the heart of Betis fans and the club even arranged a benefit match for their old manager in 1954 when they heard he was experiencing financial difficulties.

In November 1955, a young man named Dan O’Connell entered a pub in Dublin in which Spain players were relaxing following a 2-2 draw with the Republic of Ireland. He asked them if they had ever heard of a relation of his named Patrick O’Connell. “Of course we have!” they replied and told the young man they would have no trouble finding him in Sevilla.

Dan ventured there in search of the father he had not seen since childhood. As Sue O’Connell explains in her comprehensive account of the fascinating O’Connell family – an account for which she is seeking a publisher – the reunion did not go well.

Patrick later returned to London and drew national assistance while living in an attic room in his brother’s house. He died of pneumonia in 1959. He is buried in the St Mary’s Catholic Cemetery on Kensal Road in north-west London and one of the campaign’s aims is to raise funds for a more fitting memorial.